There have been many attempts to design a practical, compact, folding or flexible truss system which can transition easily between retracted and extended states when the truss system is situated in varying operating environments. Prior art truss systems were designed to exhibit specific characteristics including low size/volume ratio; high kinematic stability; simplicity and reliability; high compactability; or high structural efficiency in terms of weight, complexity, auxiliary mechanism requirements, manufacturing costs, speed of operation or operating costs. Typically, truss systems disclosed in the prior art lack an optimal combination of features. Further, some prior art trusses have undesirable characteristics including undue complexity; inability to move in a coordinated and synchronous manner; requirements for a dedicated deployer; lack of compactability, reconfigurability, and multi-functional uses; and high costs. Relatively few designs have appeared in the marketplace that have been able to incorporate desirable design features, avoid undesirable features, and reduce the complexity of the chordal and section members of the truss system. Fewer still are capable of multiple uses and of deployment in multiple gravitational or operational environments.
For example, U.S. Pat. No. 3,783,573 to Vaughn (“Vaughn”) discloses many of the desired characteristics listed above but also includes some of the undesirable characteristics. Vaughn discloses frame sets and frame bays in a parallelogram configuration that includes extra chords and members that make the design overly complex, increasing the number of components that could fail to extend or retract. Further, Vaughn discloses that collapsing the structure requires the disconnection of the structural bays from each other and the collapse of each bay separately. Thus, Vaughn's system fails to act in a continuous and synchronous manner.
One advance in the art is represented in U.S. Pat. No. 7,028,442, to Merrifield, (the “442 patent”), the teachings of which are incorporated herein by reference. The '442 patent discloses a deployable square or rectangular configured truss with many desirable characteristics. The '442 patent does not disclose, however, the triangular configuration of the present invention, which possesses distinct characteristics and advantages.
There is a continuing need for improved deployable triangular truss systems that achieve synchronous coordinated motion of all members while extending or retracting, are stable, and do not require dedicated auxiliary mechanisms and structures to function, so that the overall deployable system remains compactable and low in weight, and has both reduced complexity and cost.